A Cross-Correlation Method in Wavelet Domain for Demodulation of FBG-FP Static-Strain Sensors

Static-strain can be detected by measuring a cross-correlation of two FBG-based Fabry-Pérot interferometers (FBG-FPs). This letter addresses applying the wavelet transform to cross-correlation processing in noise-contaminated FBG-FP reflection spectrums for crust deformation measurement. Since the wavelet transform has a unique feature of varying time-frequency resolution, cross-correlation processing in the wavelet domain is more robust with correlated noise and window size and is less sensitive to nonstationary data. We discuss the experimental results in respect of the factors that could influence the sensor resolution. In addition, a staticstrain resolution of 1.3 n(varepsilon ) , higher than conventional cross-correlation method is obtained in the laboratory test by using this technique.